\documentclass{standalone}
\usepackage{tikz}
\usepackage{ctex,siunitx}
\setCJKmainfont{Noto Serif CJK SC}
\usepackage{tkz-euclide}
\usepackage{amsmath}
\usetikzlibrary{patterns, calc}
\usetikzlibrary {decorations.pathmorphing, decorations.pathreplacing, decorations.shapes,}
\begin{document}
\small
\begin{tikzpicture}[>=stealth, thick,scale=0.7]
  \draw[dashed, ->](2,0)--(11,0) node[right]{选定的正方向};
  \fill (5,0) circle[radius=2.5pt];
  \draw[very thick, ->](5,0)--node[above]{$F_1=-\qty{3}{N}$}(3.5,0);
  \fill (5,0) circle[radius=2.5pt];
  \draw[very thick, ->](5,0)--node[above]{$F=\qty{8}{N}$}(9,0);
  \fill (5,-.5) circle[radius=2.5pt];
  \draw[very thick, ->](5,-.5)--node[below]{$F_2=\qty{11}{N}$}(10.5,-.5);
\end{tikzpicture}
\end{document}